Recovery of n-(7-2&#39;-thienylacetamidoceph-3-em-3-ylmethyl) pyridinium - 4-carboxylate from an acid addition salt thereof



Much 3, 197.0v

I Filed April 3, 1967 FIG. 1.

WELENGTH (MICRONS) ADDITIONv SALT THEREOF A RISP 3,498,979

4 Sheets-Shut 1 ATTR'NEVS Mlfh 3, 1970 H. A. cRlsP 3.498.979-

RECOVERY 0F N"(72-THIENYLACETAMIDOCEPH'EM--YLETHYL)PYRIDINIUI-CRBOXYLATE FROM AN ACID:

ADDITION SALT THEREOF Filed April s. 196'? 4 sheets-sheet a o -r o 11 I2JUNI. nl..

[W RWA m A f March 3, 1970 H. A. cRlsP 3.493.979 RECOVERY OFN-(7-2-THIENYLACETAMIDOCEPH-S-EM--YLMETHYL) PYRIDINIUM4-CARBOXYLATE FROMAN ACID ADDITION SALT THEREOF Filed April 3, 1967 4 Sheets-Sheet 5 o C ocn I 5 Lu un m 0' E Q ('l.) apNvluwsNvul /NvENTORs Hmmm mes@ Cle/5P f//vFRANC/5 Unef/TON C/fmPf/EK Jol/N SHARP BY PETER 4 new W/K/NsoN Wb/WATToe/vsvs March 3, 1970 ||,'A CRISP 3,498,979

RECOVERY 0F N-(7-2'-THIENYLACETAMIDocEPH--EM--YLMETHYL)PYRIDINIUM4GARBOXYLATEFROM AN AcID- ADDITION SALT THEREOF Filed April 3,1957 4 Sheets-Sheet 4 United States Patent 3,498,979 RECOVERY OFN-(72'THIENYLACETAMIDO CEPH-3-EM-3-YLMETHYL) PYRIDINIUM 4- CARBOXYLATEFROM AN ACID ADDITION SALT THEREOF Harold A. Crisp, Harrow Weald, `lohnFrancis Oughton, Gerrards Cross, Christopher John Sharp, Northolt, andPeter Alfred Wilkinson, South Croydon, England, assignors to GlaxoLaboratories Limited, Greenford, Middlesex, England, a British companyContinuation-impart of application Ser. No. 605,474, Dec. 28, 1966. Thisapplication Apr. 3, 1967, Ser. No. 627,933

Int. Cl. C07d 99/24 U.S. Cl. 260-243 18 Claims ABSTRACT OF THEDISCLOSURE The betaine, N-(72'thienylacetamidoceph 3 ein-3- ylmethyl)pyridinium 4-car-boxylate, a broad spectrum antibiotic, is regeneratedand recovered from an acid addition salt thereof ywith an acid having apKa of not greater than 4 by contacting an organic solution of the saltwith an organic base to form an organic solution of an acid additionsalt of the base and recovering the betaine from the organic medium.Depending on the organic solvent selected, there may be obtainedparticular crystalline forms of the betaine which are relativelynon-hygroscopic compared `with the hydrogscopic forms previously prepared.

This application is a continuation-in-part of our copending applicationSer. No. 605,474, filed Dec. 28, 1966, now abandoned which latterapplication is in turn a continuation-in-part of our copendingapplication Ser. No. 408,919, led Nov. 4, 1964 and also abandoned. It isconcerned with the production of antibiotics derived from cephalosporinC.

British patent specifications Nos. 912,541 and 966,221 describe andclaim cephaolsporin CA compounds and their preparation by thecondensation of a 7-acylamidocephalosporanic acid with pyridine or liketertiary organic base in a polar medium, e.g., water. A cephalosporin CAcompound of great importance as a broad-spectrum antibiotic iscephaloridine, viz N-(7-2'-thienylacetamidoceph-3-em- 3-ylmethyl)pyridinium-4-carboxylate, which forms the subject of British Patent No.1,028,563 of the persent assignees, Glaxo Laboratories Limited.

The production of acid addition salts containing cations of the generalformula:

wherein R1 is a hydrogen atom and R2 is an acyl group and X is aquaternary amino group is described in U.S. Patent No. 3,280,118 ofEardley et al. issued Oct. 18, 1966. The anion of the salt is preferablyderived from 3,498,979 Patented Mar. 3, 1970 an acid having a pKa of 4or less. These salts are useful, inter alia, in the purification of theparent betaine, viz:

wherein R1, R2 and X have the meanings defined above. As is described inU.S. Patent No. 3,280,118 the betaine can be regenerated from the acidaddition salt by slurrying the latter in yWater with an anion exchangeresin in a weak acid form, eg., the acetate form. The resulting salt isunstable and loses the acid ion on processing to yield the betaine.

However, We have now devised an improved process for the recovery ofsaid betaine from acid additions salts. Essentially our inventionresides in the recognition of the fact that said acid addition saltshave in general different solubility characteristics in organic media tosaid betaines. By virtue of this we can dissolve the salt in an organicsolvent, convert the salt to the betaine in situ, and recover thebetaine from the reaction mixture. Although the yield of the betaine maynot be any higher than from other methods, the colour and hence thepurity of the betaine is in general improved if it is obtained by theprocess according to the invention. Moreover, the process is relativelysimple and inexpensive.

According to the invention, therefore, there is provided a process forthe recovery of betaines of general Formula II from acid addition saltscontaining cations of general Formula I which comprises effectingreaction in solution in an organic solvent between said acid additionsalt and a base, preferably a strong organic base, to for-m a solubleacid addition salt of said base and recovering said betaine from thereaction mixture.

By the expression strong organic base as used herein we mean a basehaving a pKb of less than 6.

The salts used in the process according to the invention are as dened insaid U.S. Patent No. 3,280,118 and are preferably derived from an acidhaving a pKa of 4 oz. less. We particularly prefer to use thehydronitrate salt as it forms a well-defined crystalline materialenabling one to regenerate the betaine therefrom in a high state ofpurity.

Whlst R1 may represent an acyl group in general terms, specic acylgroups which may be used include those having the general formulae:

(i) R' (CH2)nCO-where R' is aryl, cycloalkyl, substituted aryl,substituted cycloalkyl or heterocyclic group and n is an integer from1-8, preferably 1-4. The heterocyclic ring is preferably a 5- or6-membered ring containing one or more of O, S and N 0r such a ringfused to benzene. Examples of these group include phenylacetyl,nitrophenylacctyl, phenylpropionyl, cyclohexylacetyl and thienylacetyl.

(ii) CnH2n+1CO-where n is 0 or an integer from 1-7. The alkyl group maybe straight or branched and, if desired, may be interrupted by an oxygenor a sulphur atom. Examples of such groups include formyl, acetyl,hexanoyl, heptanoyl, octanoyl and butylthioacetyl.

(iii) CH2n 1CO-where n is an integer from 2-7. The alkenyl group may bestraight or branched and, if de- 3 sired, may be interrupted by anoxygen or a sulphur atom. Examples of such groups include acrlyl andalkylthioacetyl.

(iv) RO CR"R.CO-where R has the meaning deiined under (i) or is an alkylgroup and R and R" are the same or are diierent and each is a hydrogenatom r an alkyl group. An example of such a group is phenoxyacetyl.

(v) RSCR"R"'.CO*where R,R" and R" are as deiined under (iv). Examples ofsuch thio groups include S-phenylthioacetyl, S-chlorophenylthioacetyland S-bromophenylthioacetyl.

(vi) R(CH2)mS(CHz)nCRR".CO-whcre R', R" and R" are as defined under(iv), m` is an integer from l4 and n is O or an integer from 1 4.Examples of such a group include S-benzylthioacetyl, benzylthiopropionyland -phenethylthioacetyl.

(vii) RCO-where R has the meaning defined under (i). Examples of suchgroups include benzoyl, substituted benzoyl and cyclopentanoyl. Wherethe benzoyl group is substituted the substituents may be alkyl or alkoxyand the substituents may be in the 2- or 2- and -positions.

The group X preferably represents an N-pyridyl group or an N-pyridylgroup substituted, e.g., with one or more alkyl, carboxy, carba'moyl,etc., groups such as an N- picolinyl group, N-isonicotinyl group orN-riicotinamido group.

It is to be noted that in the preparation of the salt the group R1 willnot in general enter into the reaction and from this point of View isrelatively unimportant. If R1 contains a basic group this may also forma salt group and it will be appreciated that the amount of acid used mayhave to be adjusted accordingly. The group X although entering into thereaction is also relatively unimportant from this point of view.

After the reaction between the base and the acid addition salt has takenplace, recovery of the betaine may be facilitated by addition of ananti-solvent, e.g. substantially anhydrous alkanols, e.g. methanol orethanol, ethers, ketones, e.g. acetone and esters, e.g. ethyl acetate,and then collecting the resultant precipitate. Alternatively, thebetaine may be recovered by direct crystallization from the reactionmixture.

The organic solvent used in this process according to the invention ispreferably selected from those containing the following group:

Examples of such solvents are substituted amides of the general formulaR3--CO.NR1.R5 where R3 is a hydrogen atom or an alkyl group containing 1to 5 carbon atoms and R4 and R5, which may be the same or different, areeach an alkyl group containing l to 5 carbon atoms, or, alternatively,R4 and R5 together form a divalent aliphatic group which, together withthe adjacent nitrogen atom, forms a heterocyclic ring. Examples ofamides of this type are N,Ndimethylformarnide, N,N-diethylformam ide,N,N dipropylformamide, N,N dibutylformamide, N,Ndimethylacetamide,N,Ndiethylacetamide, N,Ndimethylvaleramide, N,N-dirnethylpropionamide,N-formylpiperidine and N-forrnylmorpholine. Of this group of compounds,we prefer to use N,N-dimethylacetamide or N,Ndimethylformamide. Thesetwo solvents are characterised by having good solubility power for theacid addition salts and low solubility power for the betaines. Thus whena solvent-soluble strong organic base is added to such a solution of theacid-addition salt, the betaiue can be crystallized directly from thesolution or on the addition of an antisolvent, e.g. methanol.

The N,N-disubstituted amide solvents are particularly to be preferred assolvents in the reaction according to the invention because they yieldthe betaine in crystalline forms which are relatively nou-hygroscopiccompared with the hygroscopic forms previously prepared and hencepossess important advantages in handling and formulation.

The non-hygroscopic forms of the betaines of Formula II are novelsubstances and constitute a further feature of the invention. They maybe characterised by their X-ray crystallographic constants and by otherdetails given below. Slight differences between forms crystallised from,for example, N,Ndimethylformamide (DMF) and N,Ndimethylacetan1ide (DMA)have been observed but the invention extends to all the non-hygroscopiccrystalline forms of the betaines of Formula II.

In the particular case of N-(7-2thienylacetamido ceph-3-em-3-ylmethyl)pyridinium-4-carboxylate different forms have been isolated from DMA andDMF and these will be termed herein, for convenience, the rxand -formsrespectively. X-ray crystallographic data in respect of these two formsare given in the following tables showing the value of 26 (twice theBragg angle) and the corresponding interplanar spacings in angstromsmeasured from lm taken on a Guinier powder X-ray camera using copperKot-radiation. The relative intensities of the lines are also givenaccording to the following arbitrary basis:

s=strong wzweak v=very b=broad TABLE L-a-FORM 26" d(A..) I 20 d(A.) I

6.05 14.6 vstb) 28.40 3.14 m (b) 11. 97 7.38 ms 28.97 3.08 f 12. 97 6.82f 29.75 3.00 w (b) 13.85 639 w 30.20 2.96 i 15.57 5.68 vvs 31.67 2.82 ms(b) 15.90 5.57 vvs 32.30 2.77 vw 39 mswb) 80 2.73 w-m 2 w .50 2.67 18.47 4.80 vw 33.77 2.65 im ("b) 19.77 4.49 ms (b) 34.70 258 f 21.05 4.22vs (b) 35.12 255 w-m 21.77 4.08 s (b) 35.25 2.54 w 22. 3.89 m (b) 35.722.51 w (b) 23.27 3.82 w 36.35 2.47 vvv 23.77 3.74 ms 36.90 2.43 w-m24.07 3.69 ms 37.27 2.41 f 24.27 3.66 w 37. 2.37 i 25.00 3.55 vw 38.302.35 w (b) 25.62 3.47 w (b) 38.80 2.32 vw (b) 26.30 3.38 s 40.15 2. 24W-m (vb) 26.57 3.35 ms 41.35 2.18 m 27.05 3.29 w-m 42.25 2.14 w (vb)27.82 3.20

TABLE lL-a-FORM 20 d(A.) I 26 d(A.) I

6.10 14.48 vs 26.90 3.31 w 10.62 8.32 r 27.55 3.24 vw 11.90 7.43 ms28.10 3.17 W 13.02 6.79 m 29.10 3.07 f 13.70 6.46. vw 29.67 3.01 ms (b)14.72 6.01 w 29. 2.98 vw 15.35 5.77 yvs 31.1() 2.87 W-m (b) 15.67 5. 65vvs 31.67 2. 82 m 15.02 5.56 w 32.10 2. 79 ms 16. 55 5.35 w-m 32.32 2.77vw (vb) 16. 75 5.29 33.10 2. 70} b) 17.92 4.94 vs (b) 33.40 2.68 W V18.40 4.82 w-m 34.20 2.02 f 19.20 4.62 f 34.65 2.59 w-m g; 44. w 2.582vw 2.558 w 20.62 4.30 }vs (vb) 36,12 2.48 w (b) 21.02 4.22 ms 36.45 2.46w (b) 21.70 4.00 ms (b) 36.97 2.43 w 22.37 3.97 vvs (b) 37.62 2.39 w23.05 3.86 w-m 37.97 2.37 w 23.42 3.79 wm 38.30 2.35 vw 24.02 3.70 w-rn38.82 2.32 vw (b) 24.40 3.65 i 39.27 2.30 r 24.52 3.63 t 39.02 2.26 m24.85 8.58 vw 40.30 2.241 (b) 25.20 3.53 w 40.42 2.231W 25.42 3.50 w40.77 2.21 vw 26.00 3.42 w 41.47 2.18 f 26.15 3.41 w 42.00 2.15 vv (vb)liqui ines or Yet another group of solvents are tetraalkylureas of thegeneral formula R4.RN.CONR4.R5, where R"l and R5 have the meaningsdefined a'bove. IExamples of such substituted ureas include,N,N,N,N'tetramethylurea and Solvents of a different type chemicallywhich may be employed are those of the formula R4.R5SO, where R4 and R5have the meanings defined above. An example of such a solvent isdimethyl sulphoxide.

Where the base used is itself a liquid and the acid addi tion salt issoluble therein, the base may function as the solvent for the reaction.Pyridine, for example, may be used in this way.

Where organic bases are used these are preferably liqui bove for theX-ray measurements. tertiary amines, e.g., tri(lower alkyl) am yand-forms o (ex methanol) Norm (ex water) Cnr-1 C111.'-l

Differences also exist between the infrared spectra of theaforementioned aand-forms, and FIGURES 1 and 2 of the acompanyingdrawings show infrared spectra of Nujol mulls of these two formsrespectively. For the sake of comparison, FIGURES 3 and 4 show theinfraprincipal absorption bands in both u, and cm.nl for the aand -formsas compared with those of the ry-form given a TABLE III(7-2tl1ieny1acetamidoeeph-B-em--ylmethyl)-pyridinumA-carboxylate] mfom(ex DMA) -foml" (ex DMF) y-foml" CHL-1 Cms-1 red spectra of the 'y-formcrystallised from methanol and the -form isolated from Water by freezedrying respectively. It should be noted that the spectra of the yand-forms refer to material dried to the substantially solvent-freecondition. The following table shows the (crystallised from methanol)and the -form (isolated from water). Intensities are also shown usingthe same arbitary basis rineipal absorption bands (p and cmrl) in theinfrared spectra of Nujol mulls of a ion in ions.

marks Amberlite LA2 and Amberlite LAl. These are high molecular weightsecondary amines and are almost insoluble in water.

Organic bases may be used as such or as a solut' preferred to obtain thenon-hygroscopic crystals by effectan inert organic solvent.

As an alternative to using organic bases one may use bases provided thatthese are otherwise inert to the cephalosporin derivative. Inorganicbases which may be used include alkali metal and alkaline earth metalstals. The amount of ketone employed and carbonates and bicarbonates.These may be used the rate at which it is added must be carefullyregulated if non-hygroscopic crystals of the betaine are to be 0b- Theregeneration and recovery process according to the tion may convenientlybe effected at a temperature the range of 5-60" C. The process accordingto the invention may be utilised with advantage in the manufacture ofN-(7-acylamid0- ceph-3-em-3y1methyl)pyridinium 4 carboxylates in aprocess involving the use of thiocyanate or iodide Thus, Belgian PatentNo. 652,148 describes in Example 75 10 a process for the production ofcephaloridine, involvinorganic 1 aqueous solution or in solid form.

inven The fyand -forms isolated from methanol and water 55 secondaryamines, eg., the products sold under the traderespectively arehygroscopic. It should be noted that if scopic cry minary trial. It hasbeen observed that when acetone d with dimethylacetamide, the betaine issometimes obtained as a mixture of non-hygroscopic forms. This does not,however, significantly affect the handling haracteristics of theproduct.

Another convenient group of solvents are the N,Ndi

alkylcyanamides, e.g. N,Ndimethylcyanamide.

an alcohol, such as methanol, is used as the anti-solvent to increasecrystallisation of the betaine from the substituted amide solvent, theproduct is hygroscopic. It is ing partial crystallisation of the betainefrom the substituted amide solvent and then effecting furthercrystallisation by the addition of a quantity of a lower ketone, e.g.acetone, before harvesting the desired non-hygrotained. The optimumamount may be ascertained by preli is use and formulating c ing thecondensation of 7-2'-thienylacetamidocephalosporanic acid with pyridinein an aqueous acidic medium containing potassium thiocyanate. Thecephaloridine is recovered from the reaction mixture -by treatment witha liquid anion exchanger in the acetate form. This process andvariations on it as described in Belgian Patent No. 675,299 lead to anenhanced yield of the cephalosporin C A compound but the purity of thelatter leaves much to be desired.

We have now found that N-(7-acylamidoceph-3-em-3- yl-methyl)pyridinium-4-carboxylates can be prepared in a high state of purity andgood yield by an extension of the general process we have described by aprocess which includes the following steps:

(A) Reacting a 7-acylamidocephalosporanic acid or a metal salt thereof,particularly an alkali metal salt, with a pyridine in solution in areaction medium in the presence of an at least equimolar proportion,calculated on the 7-acylamidocephalosporanic acid, of thiocyanate oriodide ions and recovering the resultantN-(7-acylamidoceph-3-em-3-yl-methyl) pyrdinium-4-carboxylate as itscrude hydrothiocyanate or hydroiodide acid addition salt;

(B) Converting the crude hydrothiocyanate or hydroiodide acid additionsalt from (A) to the betaine form by reacting said salt with a base, thebetaine being recovered in an aqueous phase and thiocyanate or iodidelimpurities preferably being separated in an organic phase;

(C) If desired, passing the aqueous phase from (B) through one or moreion-exchangers and, if desired, decolourising absorbents to removefurther impurities, e.g., acidic and basic impurities as Well ascolourants;

(D) Reacting the aqueous phase from (B) or (C) with an acid,particularly nitric acid, to form an insoluble acid addition salt;

(E) Separating the acid addition salt from (D) from the mother liquorand converting the salt to the betaine form by reaction with a base.

The acyl group on the 7amino group of the desired product and thepyridinium substituent on the S-methyl group may be any of thosedescribed above.

The betaine resulting from Step (B), i.e., on reacting thehydrothiocyanate or hydroiodide acid addition salt with a base, isconsiderably less pure than that obtained by treating the acid additionsalt of Step (D) with a base as in Step (E). The betaines from Step (B)are quite unsatisfactory for more or less direct use as pharmaceuticalgrade cephalosporin CA compounds because of residual impurities such asthiocyanate or iodide ions and traces of the corresponding A2 isomer andother impurities which are present at the end of Step (B). The acidaddition salts of Step (D) and in particular the hydronitrate salt onthe other hand are crystalline intermediates which are relatively freefrom contaminants and which give remarkably pure products on treatmentwith a base.

STEP (A) The reaction is desirably effected in the presence of a largeproportion of thiocyanate or iodide ions so that not only is there ahigh ratio of said ions to 7-acylamidocephalosporanic acid startingmaterial, preferably in a ratio of at least 2:1 and possibly up to 25:1but preferably also a high concentration of said ions in the aqueousreaction medium. Higher molar ratios vat high concentration are possiblewith thiocyanates than with iodides. Thus with alkali metal thiocyanatesmolar ratios of up to :1 can be used at high concentration. Thethiocyanate or iodide is conveniently used as an alkali metal, oralkaline earth metal salt, c g. the sodium or potassium salt. Thepyridine is conveniently used at a level of from about 1.3 equivalentsand upwards based on the cephalosporin starting material. The latter maybe used as the free acid but is conveniently used as an alkali metal,eg. sodium salt. The reaction of Step (A) may be effected at from 40 C,to 100 C.

Step (A) may be effected in solution in an aqueous reaction medium or insolution in an organic reaction medium. The number of organic solventswhich may be used is limited having regard to the diverse solubilitycharacteristics of the various reagents. It is not necessary that thereactants should dissolve in the chosen medium at room temperature butthey should be soluble at the chosen reaction temperature. Organicsolvents which can be used are necessarily highly polar but polarity initself is not a governing factor, Organic solvents which may be usedinclude formamide, N-methylformamide, N,Ndimethylformamide anddimethylsulphoxide.

At the end of Step (A) the hydrothiocyanate or hydroiodide salt isobtained from the reaction mixture, or from an aqueous phase derivedtherefrom, conveniently by acidifying and cooling to precipitate thedesired salt.

STEP (B) The conversion of the hydrothiocyanate or hydroiodide from (A)to the betaine is preferably effected by means of a two phase system, anaqueous phase for the recovery of the betaine and a water-immiscibleorganic phase containing an ion-exchanger for the removal of thiocyanateor iodide ions. This may conveniently be effected by contacting the acidaddition salt recovered from (A) with Water and a water-immiscible basicion-exchanger. The resultant mixture is then agitated until the acidaddition salt goes into solution, the resulting mixture is then agitatedwith a Water-immiscible organic solvent, the phases are separated andthe aqueous betaine-containing phase is, if necessary, further extractedwith a water-immisci'ble organic phase containing basic ion-exchanger toremove further thiocyanate or iodide ions and also, if desired, furtherextracted with a water-immiscible organic solvent. A suitable basicion-exchanger for this step is Amberlite LA-1 or Amberlite LA-2.Suitable organic solvents include halogenated aliphatic hydrocarbons,eg., carbon tetrachloride, methylene chloride, dichloroethane orchloroform.

The betaine so obtained is impure. It contains as impurities thiocyanateor iodide ions, traces of the corresponding 7-acylamidocephalosporanicacid and A2 cephalosporins and other minor impurities.

If in Step (D) the hydronitrate is formed this step may be omitted but,even when proceeding via the hydronitrate, it is advantageous to utilisethis step to remove further impurities, particularly acidic impuritieseg., free 7acylamidocephalosporanic acid, basic impurities, e.g., thecephalosporin CA compound in decarboxylated form and colourants. Thispurification step is conveniently effected by passing the aqueous phasefrom Step (B) through a column containing, in any desired order, amineral absorbent, e.g. alumina, to remove colourants; acation-exchanger, e.g. Zeo-Karb 226 (a weak cationexchange resinprepared by direct polymerisation of methacr'ylic acid anddivinylbenzene) to remove basic impurities and an anion-exchanger, e.g.,Deacidite FF or Dowex 1X8 (strong anion-exchange resins prepared fromcross-linked polystyrene resin beads by treating them with chloromethylmethyl ether followed by treatment with a tertiary amine) to removeacidic impurities.

STEP (D) AND STEP (E) The production of hydronitrate or other acidaddition salt, e.g. hydroperchlorate, hydrotetrauoroborate, hydroiodide,hydrotrichloroacetate or hydrothiocyanate of cephalosporin CA compounds.and the subsequent regeneration therefrom of the parent betaine insubstantially pure crystalline form is described in the generaldescription above.

We particularly prefer the hydronitrate as it forms a Well-definedcrystalline material ena-bling one to regenerate the betaine therefromin a high state of purity.

The conversion of the hydronitrate to the -parent betaine may beeffected in solution or suspension in an organic 9 solvent, e.g. an N,Ndisubstituted acid amide, e.g. dimethylacetamide or dimethylformamide,by reaction therein with a base, preferably a strong organic base, toform a soluble acid addition salt of said base and recovering thebetaine from the reaction mixture as described above or as described inU.S. Patent No. 3,280,118.

In order that the invention may be well understood the followingexamples are given -by way of illustration only. The hydronitrate saltof N-(72'thienylacetamido ceph-3-em-3-ylmethyl) pyridinium-4-carboxylate(see Example of U.S. No. 3,280,118) employed is used only for thepurpose of illustration and the invention is not limited to the use ofthis particular betaine or to hydronitrate salts.

EXAMPLE 1 xgg at 240 mntgm 977, inflection at 255 mpEZom 344, mm2 gi ggg1.095

and giving clear solutions in water from 1% to 20% concentrations.

EXAMPLE 2 A solution of triethylamine (0.63 g., 6.25 millimoles) inmethanol (24 ml.) was added to a solution of N-(7-2-thienylacetamidoceph-3-em-3-ylmethyl) pyridinium 4- carboxylatehydronitrate (2.4 g.; 4.98 millimoles) in N,N dimethylformamide (6 ml.)and the reaction mixture was allowed to stand at room temperature for 1hour with occasional swirling. The crystalline precipitate was collectedby filtration, washed with methanol m1,), diethyl ether (10 ml.) bydisplacement and dried in vacuo at 40 to constant weight to giveN-(7-2thienylacet amidoceph-3-em-3-ylmethyl) pyridinium 4 carboxylate(1.818 g., 87.5% of theory) with [a]D20-}-48.4 (c., 1 in water), pH 4.8(c., 1 in water),

)ggg at 24o mist@ 372, inflection at 255 maf/1m 34.1, ratioE 24 1.09

EXAMPLE 3 Triethylamine (1.01 g.; 10 millimoles) was added to a solutionof N (7-2"-thienylacetamidoceph-3-em-3-ylmethyl)pyridinium-4-carboxylate hydronitrate (2.4 g.; 4.98 millimoles) indimethylsulphoxide (6 ml.). Methanol (3 ml.) was added to obtain ahomogeneous reaction mixture. After 10 minutes, further methanol (17ml.) was added portionwise to the stirred reaction solution to give aclear solution from which the product precipitated. The reaction mixturewas stirred occasionally during one hour. The precipitate was thencollected by filtration washed with rmethanol (20 ml.) by displacementand dried in vacuo to give N-(7-2thienylacetamidoceph-3- em 3 ylmethyl)pyridinium-4-carboxylate (1.823 g.; 86.6% of theory) with [a]D2-|46.4,pH 4.9 (c., 1 in water), giving clear solutions for concentrations of 1%to 20% in water.

EXAMPLE 4 Triethylamine (2.1 ml.; 1.52 g.; millimoles) was added to astirred solution of N-(7-2'thienylacetamido ceph-3-em-3-ylmethyl)pyridinium-4-carboxylate hydroni- 10 trate (4.8 g.; 9.96 millimoles) inN,Ndimethylacetamide (48 ml.) and seeded withN-(7-2'-thienylacetamidoceph- 3-em-3-ylmethyl)pyridinium-4-carboxylate.The reaction solution was stirred at room temperature for two hoursduring which time the product crystallised out. The precipitate wascollected by filtration and washed with N,N dimethylacetamide (6 ml.)and then with acetone (20 ml.) by displacement and dried in vacuo at 40for 2 hours and then for 16 hours at 30 to give N-(7-2-thienylacetamidoceph-3em-3-ylmethyl) pyridinium-4-carboxylate (3.16 g.75.6% of theory) with [a]D20-}47.4; pH 4.5 (c., 1 in water) giving clearsolutions at 1% to 20% concentrations in water.

EXAMPLE 5 N-(7-2thienylacetamidoceph3-em-2-ylmethyl)pyridinium-4-carboxylate hydronitrate (1 g.; 2.09 millimoles) wasdissolved with stirring in a mixture of pyridine (5 ml.; 4.9 g.; 62millimoles) and methanol (5 ml.) at 40 C. After 15 minutes theprecipitate was collected by filtration, washed with a 1:1 mixture ofpyridine and methanol (10 mL), methanol (20 ml.) and dried in vacuo at40 to constant weight to give N-(72thienylacetamidoceph-3-em-3-ylmethyl)-pyridinium-4-carboxylate (0.45 g.; 52% oftheory) with [a]D20-{-45, pH 4.6 (c., 1, in water) and containing lessthan 2% of the hydronitrate by potentiometric titration.

EXAMPLE 6 Anhydrous sodium carbonate (0.53 g.; 5.0125 millimoles) wasadded to a solution of the hydronitrate (4.8 g.; 10.05 millimoles) ofN(7-2'-thienylacetamidoceph-3-em-3-ylmethyl) pyridinium-4-carboxylate inN,Ndimethylaceta mide (25 mls.) and the suspension was stirred at 40 for45 minutes. The reaction mixture was clarified by filtra.- tion. Thefiltrate was seeded with a small quantity ofN-(7-2-thienylacetamidoceph3-em-3-ylmethyl) pyridinium-4-carboxylate andstirred at room temperature for 30 minutes but no precipitate formed.Methanol (70 ml.) was then added to the stirred solution and aprecipitate slowly formed. After 1 hour the precipitate was collected byltration, washed with methanol (40 mL), and dried in vacuo at 30 for 24hours to give N-(7-.2thienylacet amido-ceph-3-em-3-ylmethyl) pyridinium4 carboxylate (2.88 g., 69% of theory) with [a]D20-l-47.8, pH 3.6 (c., 1in water) ,ggg at 24o mt Egm 366, x ma. at 255 m.. Etgm. 336

Potentiometric titration showed the possible presence of approximately3.5% of N-(7-2thienylacetamido-ceph-3- em-3-ylmethyl)-pyridinium-4-carboxylate hydronitrate.

EXAMPLE 7 N-(7-2'-thienylacetamidoceph-3-em-3-ylmethyl)pyridinium-4-carboxylate hydronitrate (9.6 g.) was dissolved inN,Ndimethylacetamide (50 ml.). Triethylamine (3.1 ml.) was added withcontinued stirring. The N-(7-2- thienylacetamidoceph-3-em-3-ylmethyl)pyridinium-4-carboxylate was collected by filtration, washed with 1:1acetone/dimethylacetamide mixture (25 mL), followed by acetone ml.) anddried at 30 in vacuo for 16 hours. Yield 7.54 g., 90.6% theory,[a]D-{46.7 (c., 1.0 in water), pH 47.5 (c., 1.0 in water).

In Examples 8 and 9 specific rotations of cephaloridine hydronitrate,hydrothiocyanate and hydroiodide were carried out in 0.1M-potassiumhydrogen phosphate solution adjusted to pH 7 by the addition oforthophosphoric acid. The above solutions were diluted with water fordetermination of ultraviolet absorption on a Unicam SP800Spectrophotometer.

EXAMPLE 8 A mixture of sodium 72'-thienylacetamidocephalosporanate (100g. 94% pure), potassium thiocyanate` (450 1 1 g.), water (100 ml.),pyridine (25 ml.) and 85% phosphoric acid (5 ml.) was stirred at 60 for5 hours.

The mixture was diluted with water (3.9 litres) and extracted threetimes with dichloroethane (each 100 ml.). The extracts were backwashedsuccessively with water (100 ml.). The combined solution and backwashwere degassed under reduced pressure to remove dichloroethane, cooled toC., and adjusted to pI-ll 2 with 6N- hydrochloric acid (85 ml.). Thesuspension was stirred at 0 C. for one hour and the crude cephaloridinehydrothiocyanate collected by ltration and washed with icecold water(500 ml.).

The wet iilter calce (270 g.) was stirred with water (170 ml.), acetone(180 ml.) and Amberlite LA-2 (90 ml.) until all the solid had dissolved.The mixture was diluted with water (325 ml.) and extracted with carbontetrachloride (450 ml.). The separated aqueous layer was extracted twicewith Amberlite LA 2 (9 ml.) in carbon tetrachloride (90 ml.) and twicewith carbon tetrachloride (90 ml.). The extracts were backwashedsuccessively with water (75 ml.). The combined aqueous solutions Weredegassed under reduced pressure, made up to 1% (v./v.) pyridine, andpassed down a column of alumina (50 g., Woelm acid) on Zeo-Karb 226 (50ml., pyridine form) and Dowex 1X8 (50 m1., acetace form) prepared in 1%vol./vol. pyridine, and eluted with 1% vol/vol. pyridine. The solutionwas collected until [01]): (1 dm.) was 0.05 and lN-nitric acid (180 ml.)added. The resulting suspension was cooled to 0 C., for 2 hours and thecephaloridine hydronitrate collected by iltration, Washed with acetone(300 ml.) and dried at 40 in vacuo to give a white crystalline product,68.35 g., 64% theory [ehrt-41.3 )t max. 238 mp.;

Lovibond colour (1 g., +4 ml. Nsodium acetate solu tion; 1 cm. cell) 0.4yellow, 0.1 red. Electrophoresis showed that the product contained atrace of impurity (the corresponding :u2-compound) running slightlyfaster than the cephaloridine.

Cephaloridine hydronitrate (60 g.) from above, was dissolved inN,Ndimethylacetamide (D.M.A.) .(300 ml.), and the solution was stirredrapidly, while triethylamine (26.25 m1., 1.5 molar equiv.) was added,and then slowly for one hour, during which time a crystallineprecipitate was formed. The reaction mixture remained pale in colour andthe precipitate was collected by filtration, washed by displacement withD.M.A. (150 ml.), followed by acetone, (720 ml.) and dried in vacuo at40 C. The white product (41.35 g., 80% of theory) had [ethyl-48.1 (c., 1in water); pH 4.7 on 1% solution in water, A max. (H2O) 240 111,11;

E193@ 387; iniieetion at 255 ma; El'm, 355

Lovibond colour (1 g. +4.41 ml. Water; 1 cm. cell), 0.6 yelow, 0.1 red.Electrophoresis showed that the product contained only a trace ofimpurity (the corresponding Az-compound) running slightly faster thanthe cephaloridine.

Acetone (5 volumes) was added to the mother liquors which were cooled to0 to obtain poorer quality cephaloridine (8.85 g., 17.1% theory).

EXAMPLE 9 (a) Preparation of cephaloridine hydronitrate from sodium7-2-thienylacetamidocephalosporanate via the hydroiodide A mixture ofsodium 7-2'-thienylacetamidocephalosporanate (20 g., 94% pure),potassium iodide (30 g.), distilled Water (20 ml.), pyridine (5 ml.) andorthophosphoric acid (0.5 ml., 88%) was stirred at 60 C. for 5 hours.The resultant syrupy solution was diluted with distilled water (380 ml.)and extracted with 1,2-dichloroethane (3x20 ml.) and the extracts wereback extracted with water (20 ml.). The aqueous layers were degassedunder reduced pressure at 25-30 C. and acidiiied to the cloud-point with6 N-hydrochloric acid, The cloudy solution was cooled to 5 C. and slowlyacidied to pH 2 with 6 N-hydrochloric acid (total volume-20 ml.). After2 hours at 2 C. the precipitate was collected by ltration, washed bydisplacement with ice-cold distilled water (100 ml.), and sucked dryusing a water pump vacuum. The Wet iilter cake was stored in the darkovernight and then shaken with Amberlite LA-2 (20 ml.), acetone (40 ml.)until all the solid had dissolved. Distilled Water (100 ml.) and carbontetrachloride (100 ml.) were added to the mixture which was shakenvigorously and then allowed to settle. The aqueous layer was run ott,re-extracted twice with Amberlite LA-2 (2 m1.) in carbon tetrachloride(20 ml.) and then with carbon tetrachloride (2X 20 ml.). The extractswere successively back-extracted with water (30 ml.). The combinedaqueous layers were degassed under reduced pressure at 25 to 30 C. andthen swirled for ten minutes with alumina (Woelm acid; 4 g.). To thesuspension, pyridine (1 ml./ 100 ml. of solution) was added and themixture was passed through a column of alumina (20 g.7 Woelm acid).Zeo-Karb 226 (20 m1., pyridine form), Deacidite FF (20 ml., acetateform) made up in 1% (v./v.) pyridine, and eluted with 1% (v./v.)pyridine. The eluate containing the product (judged by aD) wavecollected and 4 Nnitric acid (40 Inl.) was added.

The resultant suspension was stored at 2 C. for several hours, theprecipitate was collected by ltration and washed by displacement withacetone. The white crystalline product was dried in vacuo at 40 to givecephaloridine hydronitrate (10.6 g.) in 49% yield with [a]D41.3 and )tmax. (pH7) 238 my Eig@ 329 inflection 255 my:

(b) Preparation of cephaloridine from cephaloridine hydronitrate ThisWas effected by the same process as in Example S.

EXAMPLE l0 (a) Preparation of cephaloridine hydronitrate in formamdePotassium thiocyanate g.), formamide (40 ml.) and pyridine (7 ml., 87mmol) were stirred together at 80 and sodium 7 2thienylacetamidocephalosporanate (20 g., 97% pure) was added to thesuspension. After 1.75 hours at 80 the reaction suspension was dilutedwith water (600 m1.) and the resultant solution was adjusted to pH 3.5with 6 Hhydrochloric acid (l5 ml.), and kieselguhr (1 g.) was added tothe stirred suspension. The suspension was clarified by iiltration andthe stirred filtrate was cooled to 0, acidilied to pH 2 with 6N-hydrochloric acid (15 m1.) and stirred at 0 for 3 mins. Theprecipitate was collected by ltration and washed by displacement withice-cold water ml.) and sucked as dry as possible at the pump. The crudecephaloridine hydrothiocyanate (80 g.) was dissolved in acetone (50ml.), liquid anion exchange resin LA-2 (10 m1.) at 40, and then LA-2 (10ml.), carbon tetrachloride (50 ml.) and water (70 ml.) were added andthe mixture was shaken thoroughly and allowed to separate. The LA-2/carbon tetrachloride layer was run oit and the aqueous layer was washedtwice with LA-2 in carbon tetrachloride (3.5 ml. in 20 m1.) and nallywith carbon tetrachloride (20 ml.). The washes were back-extracted withwater (20 ml.) and the combined aqueous layers were degassed at 30 for30 mins. under reduced pressure with alumina (4 g., Woelm acid) present.Pyridine (1.0 ml.) was added to the degassed suspension which was addedto the top of a column of alumina Woelm acid (10 g), Zeo-Karb 225(pyridine form; 10 m1.) and Deacidite FF (acetate form; 10 ml.) made upin 1% pyridine in water and eluated with 1% pyridine as in Example 1. Tothe eluate containing cephaloridine (300 ml.) mixed with ethyl 13acetate (60 mL), 4 N-nitric acid (40 ml.) was added and the suspensionwas stored at for 30 mins. The precipitate was collected by filtration,washed thoroughlyv with acetone and dried in vacuo at 40 for 16 hours togive substantially pure cephaloridine hydronitrate (14.67 g.) in 66%yield.

(b) Preparation of cephaloridine from cephaloridine hydronitrate Thiswas effected by the same process as in Example 8.

EXAMPLE 11 (a)Preparation of cephaloridine hydronitrate inN-methylformamide Sodium iodide (25 g), N-methylformarnide (20 ml.) andpyridine ml.) were stirred together at 80 and sodium7-2thienylacetamidocephalosporanate (10 g.; 97% pure) was added to themixture. After three hours at 80 the reaction solution was diluted withwater (300 ml.) and the pH of the resultant solution was adjusted to 3.5with 6 N-hydrochloric acid. Kieselguhr (1 g.) was added, the suspensionwas stirred at 25 for 30 minutes and then filtered. The clear filtratewas cooled to 0, acidified to pH 2 with 6 N-hydrochloric acid (ca. 10ml.) and the suspension stirred at 0 for 30 minutes. The precipitate wascollected by filtration, washed by displacement with ice-cold water (50ml.) and sucked as dry as possible on the filter. The method describedin Example l0 for the treatment of the hydrothiocyanate was used toconvert the crude caphaloridine hydroiodide to purified cephaloridinehydronitrate (7.045 g.) in 63.2% overall yield.

(b) Preparation of cephaloridine from cephaloridine hydronitrate Thiswas effected by the process of Example 12 of U.S. Patent No. 3,280,118.

EXAMPLE l2 (a) Preparation of cephaloridine hydronitrate in dimethylsulphoxide Potassium thiocyanate (30 g), dimethyl sulphoxide (20 m1.)and pyridine (4.5 ml.) were stirred at 80 while sodium 7 2thienylacetamidocephalosporanate (10 g.; 97%) was added. The reactionmixture was stirred at 80 for two hours and was then cooled to 20. 'I'heresultant red solution was diluted with water (300 ml.) and acidiltiedto pH 3.5 with 6 N-hydrochloric acid (ca. 8 ml.). Kieselguhr (2 g.) wasadded to the cloudy solution and after ten minutes the solution wasclarified by filtration. The clear yellow filtrate was cooled to 0,acidified with 6 N-hydrochloric acid (8 ml.) and after 30 minutes at 0the precipitated cephaloridine hydrothiocyanate was co1- lected byfiltration and washed well with cold water. The method described inExample 8 was used to convert the crude hydrothiocyanate into purifiedcephaloridine hydronitrate (5.6 g.; 50.4% theory) with [a]D-{39.8 (c.,0.5; 0.1M, pH 7 buffer);

k max. 238 my. El'm. 312; )t inf-l. 255 mit Elgm, 290

(b) Preparation of cephaloridine from cephaloridine hydronitrate Thiswas effected as in Example 8.

EXAMPLE 13 Proceeding generally as described in Example l2 but usingN,Ndimethylformamide in place of dimethylsulphoxide, yields ofcephaloridine hydronitrate of 51.9% and 57.9% theory were obtained in(a) using potassium thiocyanate and sodium iodide respectively. Thehydronitrates were then converted to cephaloridine as described inExample 8.

We claim:

1. A process for regeneration and recovery of the betaine, N-(7 2thienylacetamidoceph-3-em-3-ylmethyl)- pyridinum-4-carboxylate, from anacid addition salt thereof with an acid having a pKa of not greater than4 which comprises contacting with an organic base having a pKb 0f lessthan 6, a solution of said salt in an organic solvent selected from thegroup consisting of an N-alkyl substituted amide, an N,Ndialkylcyanamide, a tetraalkylurea, a dialkyl sulphoxide and said basewhen liquid and said salt is soluble therein, thereby forming a solutionof an acid addition salt of said base in said solvent and recoveringsaid betaine from the organic medium.

2. A process for the regeneration and recovery of the betaine,N-(7-2-thienylacetamidoceph-3-em-3-ylmethyl) pyridinium-4-carboxylate,from an acid addition salt thereof with an acid having a pKa of notgreater than 4 which comprises contacting with an organic base having apKb of less than 6, a solution of said salt in an organic solventselected from the group consisting of an N-alkyl substituted amide, anN,Ndialkylcyanamide, a tetraalkylurea, a dialkyl sulphoxide and saidbase when liquid and said salt is soluble therein, thereby forming asolution of an acid addition salt of said base in said solvent andrecovering said betaine from the organic medium by directcrystallisation.

3. A process for the regeneration and recovery of the betaine,N(72thienylacetamidoceph-3-em-3-ylmethyl) pyridinium-4-carboxylate, froman acid addition salt thereof with an acid having a pKa of not greaterthan 4 which comprises contacting with an organic base having a pKb ofless than 6, a solution of said salt in an organic solvent selected fromthe group consisting of an N-alkyl substituted amide, anN,Ndialkylcyanamide, a tetraalkylurea, a dialkyl sulphoxide and saidbase when liquid and Said salt is soluble therein, thereby forming asolution of an acid addition salt of said base in said solvent; addingan antisolvent for the betaine to the organic medium and recovering theprecipitated betaine.

4. A process for the regeneration and recovery of the betaine,N(7-2thienylacetamidoceph-3-em-3-ylmethy1) pyridinium-4-carboxylate,from an acid addition salt thereof with an acid having a pKa of notgreater than 4 which comprises contacting a solution of said salt in asolvent of the formula where R3 is selected from the group consisting ofhydrogen and alkyl groups containing 1-5 carbon atoms and R4 and R5 areeach an alkyl group containing 1-5 carbon atoms, With an organic basehaving a pKb of less than 6 to form a solution of an acid addition saltof said base in said solvent and recovering said betaine from theorganic medium.

5. A process as defined in claim 4 in which said acid is nitric acid.

6. A process as defined in claim 4 in which said solvent isdimethylformarnide.

7. A process as defined in claim 4 in which said solvent isdimethylacetamide.

8. A process as defined in claim 4 in which the betaine is recovered bydirect crystallisation.

9. A process as defined in claim 4 in which the betaine is recovered bycontacting the solvent with a lower ketone and recovering theprecipitated betaine.

10. A process for the regeneration and recovery of the betaine, N-(7 2thienylacetamidoceph-3-em-3-ylmethyl)pyridinium-4-carboxylate, from an`acid addition salt thereof with an acid having a pKa of not greaterthan 4 which comprises contacting a solution of said salt in a solventof the formula:

where R4 and R5 are each an alkyl group containing l-5 carbon atoms,with an organic base having a pKb of less than 6 to form a solution ofan acid addition salt of said base in said solvent and recovering saidbetaine from the organic medium.

11. A process for the regeneration and recovery of the betaine, N-(7 2thienylacetamidoceph-3-em-3-ylmethyl)pyridinium-4-carboxylate, from anacid addition salt thereof with an acid having a pKa of not greater than4 which comprises contacting a solution of said salt in a solvent of theformula:

where R3 is selected from the group consisting of hydrogen and alkylgroups containing l-5 carbon atoms and R4 and R5 are each alkyl groupscontaining 1-5 carbon atoms, with an organic tertiary base having a pKbof less than 6 to form a solution of an acid addition salt of said basein said solvent and recovering said betaine from the organic medium.

12. A process as defined in claim 11 in which said base is atri(loweralkyl)amine.

13. A process for the regeneration and recovery of the betaine,N-(7-2-thienylacetamidoceph-3em-3ylmethyl) pyridinium-4-carboxylate,from its hydronitrate salt which comprises contacting a solution of saidsalt in N,Ndi methylacetamide with a tri(loweralkyl)amine and recoveringsaid betaine from said solvent.

14. A process for the regeneration and recovery of the betaine, N-7-2-thienylacetamidoceph-3-em-3ylmethyl pyridinium-4-carboxylate, fromits hydronitrate salt which comprises contacting a solution of said saltin N,Ndimethylformamide with a tri(loweralkyl)amine and recovering saidbetaine from said solvent.

15. In a process for the preparation of N(72thienyl acetamidoceph-3-em-3ylmethyl) pyridinium4carboxylate the steps Which include (A) reacting 72 thienylacetamidocephalosporanic acid or an alkali metal salt thereofwith pyridine in solution in a reaction medium in the presence of an atleast equimolar proportion, calculated on the 7-acylamidocephalosporanic acid, of thiocyanate or iodide ions andrecovering the resultant N-(7-2thien ylacetamidoceph-3-em 3 ylmethyl)pyridinium-4- carboxylate as its crude hydrothiocyanate or hydroiodideacid addition salt;

(B) converting the crude hydrothiocyanate or hydroiodide acid additionsalt from (A) to the betaine form by contacting said salt with a base,the betaine being recovered in an aqueous phase;

(C) if desired passing the aqueous phase from (B) through at least oneion-exchanger and, if desired, decolourising absorbent;

(D) reacting the aqueous phase from (B) or (C) with an acid having a pKaof not greater than 4 to form an insoluble acid addition salt;

(E) separating the acid addition salt from (D) from the mother liquorand converting the salt to the betaine form by contacting with anorganic base having a pKb of less than 6, a solution of said acidaddition salt in an organic solvent selected from the group consistingof an N-alkyl substituted amide, an N.N dialkylcyanamide, atetraalkylurea, a dialkyl sulphoxide and said base when liquid and saidsalt is soluble therein, thereby forming a solution of an acid additionsalt of said base in said solvent; and

(F) recovering said betaine from the organic medium.

16. A process for the preparation N-(7-2thienylacetamidoceph-3-em-3-ylmethyl) pyridinium-4 carboxylate which includes thefollowing steps:

(A) reacting an alkali metal 72'thienylacetamido cephalosporanate withpyridine in an aqueous medium in the presence of an at least equimolarproportion, calculated on the 7-acylamidocephalosporanic acid, ofthiocyanate ions and recovering the resultant crudeN-(7-2'-thienylacetamidoceph 3 em-3-y1- methyl) pyridinium-t-carboxylatehydrothiocyanate;

(B) converting the crude hydrothiocyanate from (A) to the betaine formby reacting said salt with a base, thiocyanate impurities beingseparated in an organic phase and the betaine being recovered in anaqueous phase;

(C) passing the aqueous phase from (B) through at least oneion-exchanger to remove further impurities',

(D) reacting the aqueous phase from (C) with nitric acid to formN-(7-2thienylacetamidoceph-3-em-3- ylmethyl) pyridinium-l-carboxylatehydronitrate;

(E) separating the hydronitrate from (D) from the mother liquor andconverting the hydronitrate to the betaine form by contacting with anorganic base having a pKb of less than 6, a solution or suspension ofsaid hydronitrate in an organic solvent selected from the groupconsisting of an N-alkyl substituted amide, an N,Ndialkylcyanamide, atetraalkylurea, a dialkyl sulphoxide and said base when liquid and saidhydronitrate is at least partially soluble therein, thereby forming asolution of the hydronitrate of said base in said solvent; and

(F) recovering said betaine from the organic medium.

17. A Iprocess as defined in claim 16 wherein said base in Step (E) istriethylamine.

18. A process as claimed in claim 16 wherein said solvent in Step (E)has the formula:

References Cited UNITED STATES PATENTS 11/1965 Flynn. 10/ 1966 Eardleyet al.

NICHOLAS S. RIZZO, Primary Examiner

